the Norwegians bill is 270 mln Euros/month and they get no rebates and are obliged to take immigration.
I'll bet that our bill will be far higher, the so called 380 mln gross (before rebates, sector subsidies (such as Agriculture), grants and projects, research support, the benefits of secondary services and inward investment) represented only 0.6% of GDP - a Thatcher legacy - others in the EU pay between 1 and 1.5% GDP. It was just that our economy has grown so much that the actual Euro figure paid was so large - in practice, it could have been double and I think will certainly exceed what we were paying before.